The Zika virus is known to cause devastating damage to the brains of developing fetuses and now there is evidence that the virus could be more damaging to adults than has been believed, NBC News reported.

Italian researchers say they've found evidence Zika can affect the brains of adults, and may damage memory. A letter published in the journal Emerging Infectious Diseases describes the case of a 32-year-old volunteer nurse infected with Zika in the Dominican Republic, who was treated for rash, headache and weakness.

"In our case, the patient reported early neurologic symptoms and moderate memory impairment in neuropsychologic examinations, all features consistent with the diagnosis of Zika virus-related encephalitis," the team at the National Institute for Infectious Diseases Lazzaro Spallanzani in Rome wrote. The doctors cited a recent study showing Zika might affect the adult brain.

Still, doctors stress that most people infected with Zika have very mild symptoms and often do not even know they have it.